The most common and most likely answer to this crossword clue is the 10 letter word EXPIRATION
I've seen this crossword clue in The Times
E
X
P
I
R
A
T
I
O
N
Buddy explains!
The straight part
We know that "coming to an end" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case coming to an end = expiration.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does EXPIRATION mean?
EXPIRATION noun- The act of expiring.
- The act or process of breathing out, or forcing air from the lungs through the nose or mouth
- Emission of volatile matter; exhalation.
- The last emission of breath; death.
- A cessation, extinction, ending
- That which is produced by breathing out, as a sound.